(CNN) -- Ashley Hewitt spent 16 years rising through the ranks of corporate human resources, reaching manager and director positions. But after having her third child, a full-time career proved too much.

Ashley Hewitt left a corporate career to raise her three children. She now works as a high-skilled temp.

Even cutting her hours back to 36 a week turned out to be more of a problem than a solution.

"I was trying to be a full-time mom and a full-time employee with part-time hours for both and it just wasn't working well," Hewitt said.

In 2006, she took a voluntary severance package from Duke Energy, her longtime employer, and became one of many professional women who leave the work force at the peak of their careers to focus on their families.

But such new stay-at-home moms can also be the perfect match for companies seeking highly-educated and skilled workers for temporary work.

"They're realizing that ... this is a talent pool that's experienced and professional and efficient and ready to work as long as they're given a little bit of consideration to their personal needs," said Allison O'Kelly, CEO of Mom Corps.

The Atlanta, Georgia, company is one of several staffing agencies formed in recent years to connect career-women-turned-stay-at-home moms with employers. On-Ramps, Flexible Executives, Flexible Resources and FlexWork Connection have similar missions. Watch why there's a need for 'on-demand top talent' »

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Hewitt, 40, said she didn't want to quit working "cold turkey." She submitted her resume to Mom Corps in 2006 and currently works about 10-14 hours per week out of her home in Charlotte, North Carolina, doing human resources work on contract for Wachovia.

"I like the fact that I can do this work and the people that I'm working for... understand that it's only one aspect of my life," Hewitt said.

"They also understand that I'm trying to do this flexibly so I may not be available at 2 o'clock for a conference call because all the kids are coming off the bus."

Money not the top motivator

Mom Corps founder O'Kelly, 35, knows first hand about the tug of war between career and family.

The Harvard Business School graduate was a manager at Toys R Us when she had her first child. The baby had health problems that forced her to frequently miss work.

"I was having a really tough time with that because that just isn't my style," O'Kelly said.

Working Moms

 71% of U.S. women with children work or are looking for work

 55% of U.S. women with children under a year old are in the labor force

 24% of U.S. working mothers have a part-time job

Source: U.S. Department of Labor

She left the company and began working on contract as an accountant. She ended up with so much work that she offered some of it to her friends. O'Kelly said she soon realized there was enough demand to expand beyond accounting and her circle of acquaintances. Mom Corps was born in 2005.

The company now has 25,000 job seekers in its database, many with marketing, human resources or accounting backgrounds. About 90 percent have a college degree and more than a third have a graduate degree, O'Kelly said. Most are 30-44 years old. Once placed, they typically earn $30-$70 an hour, O'Kelly said.

While the earnings can be high, the money isn't the primary motivator for many of the stay-at-home moms seeking flexible work. Some simply want to stay plugged into their industries and use their skills.

"I think it's probably something that they're missing from a personal, professional point of view, just part of their self-identity is very attached to their career and having to let that go is a big struggle," said Jessica Riester, founder of FlexWork Connection in Irvine, California.

Riester, 35, launched her recruiting business earlier this year after deciding to take some time off from her career to have children. The former finance manager at a start-up company soon landed a part-time corporate job, working 20 hours a week, and realized other professional women were very interested in the arrangement.

"I was telling my friends about this new setup and they were all jealous and wanted something similar," Riester said. "[They] all kind of struggled with wanting to have some kind of career going but also have the time to spend with their kids, not working the crazy hours that we had been."

'New normal of flex careers'

The demands of a full-time job appear to be taking their toll on working mothers. About 60 percent said working part time would be ideal for them, according to a 2007 survey by the Pew Research Center. Only 48 percent felt that way in a similar poll done 10 years earlier.

For those who don't want to work full time, turning to staffing agencies that cater to stay-at-home moms can be one option.

The trend reflects "the new normal of flex careers," said Ellen Galinsky, president and co-founder of the nonprofit Families and Work Institute.

"There's been an assumption for a long time that a career is a straight and narrow ladder that one climbs and if one steps off of it then you're down at the bottom or if you even step sideways, you plunge, and you climb that ladder until you leap over an abyss ... to retirement" Galinsky said.